A typical aircraft has landing gear comprising a plurality of wheeled landing gear assemblies which support the aircraft when it is on the ground. The landing gear assemblies are used to control the movement of the aircraft during ground manoeuvres such as landing, taxiing and take off. A typical large jet-powered aircraft includes a steerable nose landing gear (NLG) assembly located towards the front of the fuselage and a plurality of main landing gear (MLG) assemblies located rearwards of the NLG assembly and distributed laterally about the aircraft's plane of symmetry. The MLG assemblies typically each include one or more actuators which are operable to provide a braking force and/or driving force to decelerate and/or accelerate, respectively, the wheels of that MLG assembly.
In certain conditions the pilot of an aircraft may command differential braking of the left and right MLGs—higher braking of the left MLG giving a left turn and higher braking of the right MLG giving a right turn.
U.S. Pat. No. 4,646,242 discloses an automatic braking function which applies a constant deceleration during a de-rotation phase of an aircraft, which is the phase after the MLGs have touched down during landing but before the NLG has touched down. The automatic braking function is selected by the flight crew prior to landing by setting a deceleration selection switch to the desired deceleration level. A problem with the automatic braking function of U.S. Pat. No. 4,646,242 is that it makes no provision for differential braking.